The invention relates to the control of the drivability mode of hybrid motor vehicles, in particular those provided with a heat engine and an electric engine.
The conventional motor vehicles are generally provided with a heating system with an air heater transferring heat given off by the heat engine to a volume of heating water. The duly heated water conveys its energy by transferring it to the air of the vehicle interior.
These days, hybrid vehicles are known, for example comprising a heat engine and an electric engine powered by a battery. These vehicles are also provided with a system for controlling the drivability mode, the function of which is to control the starting up of one and/or of the other of the two engines. Some controls of the drivability modes are also capable of running the electric engine in generator mode.
Conventionally, the system for controlling the drivability mode assigns different drivability modes according to different driving situations, such as starting, moving at cruising speed, accelerating, decelerating, stopping the vehicle. For example, when accelerating, the control system generally activates both of the engines of the vehicle, the electric engine relieving the heat engine. When decelerating, the electric engine logically operates as engine brake, that is to say as a generator so as to recharge the battery of the vehicle while exerting a braking action thereon.
In some vehicles, the assignment of a drivability mode depends also on the level of charge of the battery. In effect, if the vehicle accelerates with a fully charged battery, the control system can decide to start up only the electric engine. The result thereof is less significant consumption and pollution.
Thus, in a hybrid vehicle provided with a heating device, it may be that the intermittent operation of the heat engine disrupts the operation of the heating by reducing the temperature of the heating water. This disruption results in reduced comfort for the driver and increased fuel consumption.